Much has been written on the essential features and potential benefits of the Justin-Time production system. Using a simulation model, some salient parameters such as (a)scheduling rules, (6) the effects of pull demands level, (c) the effects of the production Kanban size and the minimum Kan ban level, and (d) the significance of the job mix are evaluated. The study shows that a common prevailing practice of assigning greater priorities to jobs with higher pull frequencies is not as efficient as a shortest process time based rule. Unlike the traditional ‘push’ method, raising the pull demand in a JIT system does not ensure a high process utilization level. Results also show that an increase in the production Kanban size and minimum output Kanban level improve the mean job tardiness but causes an escalation in the output Kanban inventory level. Contrary to common conjecture, an enlarged product mix would actually produce better process utilization and mean job tardiness.